There is a noncooled version but that would loose a major feature of the camera.
You can get most of the benefit of cooling by a set of -10 or -15 rather than -20. After initial cooling the power consumption drops significantly.
There are many lithium battery packs available. Check out the 12 v "starter" batteries available on Amazon and other places for about $50. Be aware that the 18 Ah rating is at 3 volts and at 12 v they provide about 5 Ah in my tests.
I have bought cheap lead acid starters at Harbor Freight at my destination and then donated them to a local Astronomy club when leaving. I have also been able to borrow equipment from local clubs at destinations.
